direct-io.hg

changeset 7478:2c0b3b807756

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Enable TSC-offsetting capability to ensure that VMX
guest's TSC remains in sync with virtual-PIT interrupts.
This avoids the following message from full-virt Linux:
"Losing too many ticks!
TSC cannot be used as a timesource. =20
Possible reasons for this are:
You're running with Speedstep,
......"

Signed-off-by: Eddie Dong <eddie.dong@intel.com>
Signed-off-by: Edwin Zhai <edwin.zhai@intel.com>
author kaf24@firebug.cl.cam.ac.uk
date Sun Oct 23 16:54:51 2005 +0100 (2005-10-23)
parents 5a7baecb1c70
children 5a728a884242
files xen/arch/x86/vmx_intercept.c xen/arch/x86/vmx_io.c xen/include/asm-x86/vmx.h xen/include/asm-x86/vmx_virpit.h xen/include/asm-x86/vmx_vmcs.h
line diff
     1.1 --- a/xen/arch/x86/vmx_intercept.c	Sun Oct 23 16:51:47 2005 +0100
     1.2 +++ b/xen/arch/x86/vmx_intercept.c	Sun Oct 23 16:54:51 2005 +0100
     1.3 @@ -254,6 +254,8 @@ void vmx_hooks_assist(struct vcpu *v)
     1.4                     vpit->init_val);
     1.5              vpit->period = 1000000;
     1.6          }
     1.7 +         vpit->period_cycles = (u64)vpit->period * cpu_khz / 1000000L;
     1.8 +         printk("VMX_PIT: guest freq in cycles=%lld\n",(long long)vpit->period_cycles);
     1.9  
    1.10          vpit->channel = ((p->u.data >> 24) & 0x3);
    1.11          vpit->first_injected = 0;

     2.1 --- a/xen/arch/x86/vmx_io.c	Sun Oct 23 16:51:47 2005 +0100
     2.2 +++ b/xen/arch/x86/vmx_io.c	Sun Oct 23 16:54:51 2005 +0100
     2.3 @@ -799,6 +799,7 @@ static inline void
     2.4  interrupt_post_injection(struct vcpu * v, int vector, int type)
     2.5  {
     2.6      struct vmx_virpit *vpit = &(v->domain->arch.vmx_platform.vmx_pit);
     2.7 +    u64    drift;
     2.8  
     2.9      switch(type)
    2.10      {
    2.11 @@ -812,6 +813,13 @@ interrupt_post_injection(struct vcpu * v
    2.12                  vpit->pending_intr_nr--;
    2.13              }
    2.14              vpit->inject_point = NOW();
    2.15 +            drift = vpit->period_cycles * vpit->pending_intr_nr;
    2.16 +            drift = v->arch.arch_vmx.tsc_offset - drift;
    2.17 +            __vmwrite(TSC_OFFSET, drift);
    2.18 +
    2.19 +#if defined (__i386__)
    2.20 +            __vmwrite(TSC_OFFSET_HIGH, (drift >> 32));
    2.21 +#endif
    2.22   
    2.23          }
    2.24          break;

     3.1 --- a/xen/include/asm-x86/vmx.h	Sun Oct 23 16:51:47 2005 +0100
     3.2 +++ b/xen/include/asm-x86/vmx.h	Sun Oct 23 16:54:51 2005 +0100
     3.3 @@ -65,6 +65,7 @@ extern unsigned int cpu_rev;
     3.4      CPU_BASED_MWAIT_EXITING | \
     3.5      CPU_BASED_MOV_DR_EXITING | \
     3.6      CPU_BASED_ACTIVATE_IO_BITMAP | \
     3.7 +    CPU_BASED_USE_TSC_OFFSETING  | \
     3.8      CPU_BASED_UNCOND_IO_EXITING \
     3.9      )
    3.10  

     4.1 --- a/xen/include/asm-x86/vmx_virpit.h	Sun Oct 23 16:51:47 2005 +0100
     4.2 +++ b/xen/include/asm-x86/vmx_virpit.h	Sun Oct 23 16:54:51 2005 +0100
     4.3 @@ -19,6 +19,7 @@
     4.4  struct vmx_virpit {
     4.5      /* for simulation of counter 0 in mode 2*/
     4.6      u32 period;		/* pit frequency in ns */
     4.7 +    u64 period_cycles;	                /* pit frequency in cpu cycles */
     4.8      s_time_t scheduled;                 /* scheduled timer interrupt */
     4.9      unsigned int channel;  /* the pit channel, counter 0~2 */
    4.10      unsigned int pending_intr_nr; /* the couner for pending timer interrupts */

     5.1 --- a/xen/include/asm-x86/vmx_vmcs.h	Sun Oct 23 16:51:47 2005 +0100
     5.2 +++ b/xen/include/asm-x86/vmx_vmcs.h	Sun Oct 23 16:54:51 2005 +0100
     5.3 @@ -96,6 +96,7 @@ struct arch_vmx_struct {
     5.4      struct msr_state        msr_content;
     5.5      struct mmio_op          mmio_op;  /* MMIO */
     5.6      void                    *io_bitmap_a, *io_bitmap_b;
     5.7 +    u64                     tsc_offset;
     5.8  };
     5.9  
    5.10  #define vmx_schedule_tail(next)         \